“2013 Test Sessions: Cannondale Jekyll MX”

Introduced in 2011, the Cannondale Jekyll has a very fitting name given its two-sided personality. With the flip of a switch, the custom DYAD RT2 pull shock transforms the ride from a 150mm travel bump gobbling machine to one with just 90mm of rear travel and steeper angles ready to haul you back to the top for another run. Of the five models in the Jekyll lineup, the Jekyll MX was most inspired by the builds used by Cannondale's professional OverMountain enduro race squad and is the burliest of them all. Ready to rally, we gave it all we had at our 2013 Test Sessions in Southern Utah.

Jekyll MX Highlights

SmartFormed alloy frame

26-inch wheels

150/90mm adjustable rear wheel travel via a FOX DYAD RT2 shock

1.5-inch head tube

67.8-degree head angle

73.5-degree seat angle

350mm (13.8-inch) bottom bracket height

428mm (16.9-inch) chainstay length

BB30 bottom bracket with ISCG03 tabs

142x12mm rear axle

Measured Weight (size Medium): 31-pounds 15-ounces (14.5kg)

MSRP $4,880

The Jekyll MX model falls right smack dab in the middle of the Jekyll range, at the top of the alloy specs and just below the carbon versions. The bike uses SmartFormed aluminum throughout, which Cannondale claims to "deliver incredibly precise wall thickness distribution and tube shapes, concentrating material exactly where needed to maximize stiffness and strength, while shaving every last extraneous gram from the structure. Internally, all butting is accomplished via smooth, tapered transitions to eliminate the abrupt changes in material thickness which cause stress-risers." The massive tubeset is brought together using double-pass smooth welds and then heat-treated to firm everything up.

Main frame details include a low direct mount front derailleur, Syntace X-12 thru-axle and dropout system, burly derailleur hanger, ISCG03 tabs, 1.5-inch headtube, and a rubberized downtube protector. Cable routing is entirely external, with the derailleur cables following the underside of the downtube.

Out back, the swingarm and linkage are based around what Cannondale calls their "Enhanced Center Stiffness–Torsion Control" system, or ECS-TC for short. The premise is simple, and comes down to the simple fact that a frame is only as stiff as its weakest link. To really beef up the rear end, the Jekyll uses 15mm thru-axles at the key pivots combined with widely spaced axle bearings and a collet sleeve bearing preload system. The axles are clamped by bolts on both sides, resulting in a stiffer structure. Finally, they double-stack bearings in each rear pivot to increase resistance to twisting loads.

Suspension wise, things get really interesting thanks to the use of a proprietary pull shock known as the DYAD RT2. Developed in conjunction with FOX specifically for the Jekyll, the DYAD RT2 offers handlebar remote cable-actuated travel adjustment from 150mm (known as "Flow" mode) to 90mm ("Elevate" mode). Setup requires the use of a Cannondale supplied high-pressure shock pump. The recommended settings give a sag range of 33%-40% in Flow mode, which is deeper than any other FOX air shock. This is something they can get away with thanks to the inclusion of Elevate mode for climbing efficiency.

To really envision what's going on, it's best to think of the DYAD RT2 as two separate shocks combined into one. Depending on the handlebar remote setting, the oil displaced by the center pull chamber will go into one or both sides.

In Flow mode, the bike gets the full 150mm of travel and utilizes both positive air chambers and its own damping circuit. Doing so yields a high-volume air shock and linear feel, especially when combined with the frame's near linear leverage curve.

In Elevate mode, the bike gets just 90mm of travel. This occurs because the shock is trying to pump all of the available oil into just one chamber and there simply isn't enough volume. Because of this, the sag point changes and the spring rate becomes more progressive. This steepens the bike's sagged head and seat tube angles, picks the bottom bracket up a bit, and provides a firmer pedaling platform.

The two modes have different compression and rebound damping characteristics. High-speed rebound and compression are factory-tuned, but low-speed rebound for both Flow and Elevate modes is user adjustable. The center chamber also includes a shared negative air chamber that affects how easily the shock compresses initially.

While it may sound complicated, the shock is decently accessible and a tuning guide on the frame is a quick and easy reference. Shock setup took us five minutes or less. Pretty simple, really.

On The Trail

Technical bits aside, how did the Jekyll MX ride? We hit a few different trails to find out. First, Steve piloted it up and down Barrel Trail to Sidewinder in St. George, Utah, which gave us some good impressions of the bike's climbing abilities, cornering prowess, and handling over some high-speed rocky sections. Later, both Joe and Brandon took it for a few hot laps in Bootleg Canyon, navigating the Boy Scout, Girl Scout, and Inner Caldera trails. Bootleg's terrain is much like you'd expect riding on Mars would be - rocky and loose as can be.

Right off the bat, we have to applaud Cannondale for including bars of a decent width and a reasonably short stem. At 740mm wide, the stock bars will get the job done well for most riders, though if it were our bike we'd likely still opt for something a tad wider. Sizing is a bit short, and at 23.1-inches the top tube on our size Medium test bike was definitely a bit cramped - so much so that we'd recommend sizing up and running a shorter stem if needed. While we felt centered on the bike, we were surprised by how high up we felt, and we'll attribute much of that feeling to how high up the bars were. By combining the large axle-to-crown length of the FOX 36 with a relatively big 5.3-inch headtube, thick headset top cap, stem with a slight rise, and riser bars, Cannondale ended up with a bar height that's likely equivalent to many downhill bikes.

While a 0-degree stem and small headset top cap will help alleviate the over the top feeling to some extent, the bike has a slightly steep 67.8-degree head angle and relatively tall 13.8-inch bottom bracket height, both of which add to the feeling. Interestingly, the head angle ranges from 67.7 to 68-degrees, depending on the size of the frame. We'd argue that a bike with 150mm of travel and equipped with a FOX 36 should be a tad slacker.

On the other hand, the spec'd angles made the bike very precise, allowing it to handle moderate speed sections, turns, and jumps quite well. It also made it very easy to get the front end up which made it a fun, playful ride. The stout oversized downtube and ECS-TC system worked wonders toward stiffening the bike up, letting us know exactly where our wheels were at any given moment. Combined with the geo, this made it easy to switch lines.

Thanks to the rear suspension performance it was stable at most speeds, encouraging us to go faster. While the Jekyll was confidence inspiring in the sense that we never thought it would treat us badly, trusting it fully didn't come as naturally as other more aggressive bikesdue to that overwhelming over-the-top feeling. This ultimately made us a little shy of opening it up to the extent that the rear end and build kitwantedto allow.

The recommended suspension settings were almost spot on for our riding styles, requiring only minor rebound adjustments once on the trail. Flow mode had a very active, linear, and plush feel to it, especially for a bike with an air shock. It was good over small bumps, stuck to the ground in chatter, and handled every form of bump well. Square edge performance was quite impressive, with almost no hang ups and pretty good ability to maintain speed through the rough. Big hits and g-outs were stable as well. Pumping was met with good mid-stroke support, allowing the bike to pick up speed pretty quickly.

Standing and sprinting in Flow mode, however, the bike felt somewhat heavy and didn't respond to inputs as fast as we hoped. There was bob in both the small and large chainrings, but only when really pushing harder gears. When pointed uphill or on mellow sections, flipping the bar-mounted lever to the shorter travel Elevate mode made the bike a good deal more efficient. There was noticeably less bob, making it get up and go a bit faster.Though a little cramped, Elevate mode geometry felt upright, comfortable and like we just needed to put along and get to the top eventually. There wasn't a huge sense of urgency to the ride while climbing.

At a weight of nearly 32-pounds, about two pounds heavier than similarly priced bikes, the Jekyll MX could really benefit from faster rolling tires, helping to alleviate the somewhat sluggish feeling we experienced. As is the bike only really feels light once up to speed.

One tip - when switching from Elevate back to Flow mode, use the side of your finger, not your thumb, to make the switch. Though not intuitive or super easy to use at first, we appreciated not having to remove our thumb from the bar when dropping into the gnar.

Build Kit

Intended for and inspired by the enduro race crowd, the Jekyll MX has a pretty stout build. Led by the impressively stiff Performance Series FOX 36 Float R up front, the WTB Stryker wheelset, 2.3-inch WTB tires, MRP 2X guide, RockShox Reverb adjustable seatpost, and Shimano XT brakes also mean business. Note that the fork only has a rebound adjustment, so dialing it in on the fly is harder to do than one equipped with compression settings.

Braking performance was solid, and the Shimano XT stoppers and dual 180mm rotors did a great job of slowing us down at all times without any fade issues. One issue that became apparent during setup, though, was the glaring incompatibility of the XT brake levers and RockShox Reverb remote. The two don't mesh well, and the issue is worsened by Cannondale's wide grips. Because the new XT levers are quite short, if you ride with your hands at the ends of the bars, the brakes need to be against the grip or close to it. This means the seatpost lever has to be way inboard, which is a bummer on the trail.

Drivetrain performance was pretty solid, despite the odd combination of a SRAM X7 front derailleur, SRAM X7 crankset, Shimano XT rear derailleur, Shimano cassette, and KMC chain. While we didn't have any dropped chains, there was a good deal of drag and noise due to the MRP 2X guide.

The WTB Vigilante and Moto tires had good grip, providing great cornering, braking, and loose over hard performance, but they rolled very slowly as mentioned before. If you value traction over rolling, then keep these on. If you want to roll, swap them out, at least the rear.

Long Term Durability

All in all, the Jekyll MX seems to be very well made and down for the long haul. Our only concern is the use of a proprietary shock, which may or may not be in production or service forever. While we found it to be reliable in our short term test, replacement availability is something to consider, especially in race scenarios.

What's The Bottom Line?

The Cannondale Jekyll MX offers a race-ready build out of the box, impressive suspension performance almost across the board, and a responsive, stiff, playful, and fun feel. For some, like us, fun is different from very good, though, especially given the bike's racing intentions. The parts spec and suspension are worthy of absolutely letting it rip, but old school geometry holds the Jekyll MX back from what it could otherwise achieve. We think it's best suited for those that don't want to spike pedals, appreciate a high front end, and whose trails aren't super aggressive or high-speed on the way down.

About The Reviewers

Steve Wentz - A man of many talents, Steve got his start in downhilling at a young age. He has been riding for over 17 years, 10 of which have been in the Pro ranks. Asked to describe his riding style he said, "I like to smooth out the trail myself." Today he builds some of the best trails in the world (and eats lots of M&M's).

Joe Schneider - During the day, Joe's busy solving complex mechanical engineering problems. When he's free, he's out crushing miles on his bikes and moto. He raced cross-country for several years, made an appearance on the Collegiate National Champs Omnium, turned Pro, and more recently shifted his focus to enduro.

Brandon Turman - Brandon likes to pop off the little bonus lines on the sides of the trail, get aggressive when he's in tune with a bike and talk tech. In 13 years of riding he worked his way through the Collegiate downhill ranks to the Pro level. Nowadays he's Vital MTB's resident product guy.

“I love my Jekyll MX”

The Bad: A bit heavy at 31.9 lbs with pedals, the fork's damping is basic, a tool-free rear axle would be nice

Overall Review:

I’ve been riding my Jekyll MX for about 6 months and have been really pleased. My impressions right out of the box were similar to what the Vital review said, but with a few tweaks to setup, the bike feels absolutely dialed. I live in Vancouver, BC and this is my one and only bike. My riding includes a bit of everything, from laps on the Shore to all-day XC epics in Squamish and a few enduro races.

The bike feels lively, stable and laterally stiff. While some bikes like to keep wheels on the ground and soak up everything, the Jekyll feels a bit firmer and more progressive, riding higher in its travel. The rear suspension feels poppy with a well-supported mid-stroke and does not wallow like the Giant Reign I was on previously.

Being able to adjust rear travel on the fly is awesome. I use the Dyad remote a lot during a ride. I'll switch into the short travel setting right before a punchy climb and also during a smoother section of trail that requires pumping. As mentioned in the Vital review, the bike'ssuspension is quite active under pedalling in the long-travel mode, especially when mashing standing up. But having the Dyad lever compensates for that, giving the advantages of an active single-pivot design while providing good pedalling when needed. Also, the short-travel Dyad setting feels livelier than acomparable Pro-Pedal setting, firming up the suspension significantly without feeling over-damped like Pro-Pedal. It goes without saying but the bike climbs really well in the short-travel setting.

The bike's components are great out of the box and really haven’t left me with much to upgrade. The only real improvement I would want for a bike of that cost is adjustable compression damping on the fork, and maybe a front travel-adjust feature to match the rear. Otherwise, the XT components are excellent, the bars are adequately wide, the seat is comfortable and the wheels are light and easy to set up tubeless.

After spending some time to find my ideal suspension settings, the geometry feels perfect. The head angle is in fact around 66.5 degrees with the Fox 36 fork, in line with other bikes in the category (the numbers listed on the Cannondale website are for a Fox 32 150, and the bike as set up on the MX is about a degree slacker). Bottom bracket height is around 14” when un-sagged, at the higher end of the spectrum but feels fine when rear sag is set up properly.

The fork has a fairly basic R damper and tends to dive. I am running 20 psi more than what is recommended for my weight. The good news is that small bump sensitivity is still good even with the increased air pressure. I can see how the bike would feel too steep if running the recommended setting and I suspect that may have contributed to the perception of steepness in the Vital review.

For my rear air settings, I am running what is recommended for my weight without riding gear on. It feels great. The air settings recommended for my geared-up weight are too firm.

As mentioned in the review, the bars are really high up with the standard setup. I flipped some headset spacers around and eventually got a zero-rise stem, and this made a huge difference. The bike feels more balanced on the trail and I am able to keep the front end down more easily on climbs.